A scanner is a device used to create a digital image from a printed page or from a 3-dimensional object placed on a scanning bed. There are many types of scanners, for example sheet feed scanners, flatbed scanners with/without automatic document feeder (ADF), stand-alone scanners and scanner integrated into multifunctional printers.
A scanner generally irradiates light onto document by using a light source and performs photoelectric transformation of reflected light from the irradiated light using an image sensor to generate image data. An example of the image sensor may be a contact image sensor (CIS). The CIS includes a light source which generates red, green and blue light for illuminating the document, a rod lens array and a sensor array which senses the reflected light from the document.